In general, the water pressure transfer method is a method for supplying and floating on a surface of water flowing in a transfer tub a transfer film having a predetermined print pattern of non-water solubility applied on a water-soluble film of polyvinyl alcohol, making wet the water-soluble film of the transfer film with water, immersing an article (an object to be pattern-transferred) into the water in the transfer tub while contacting the transfer film, and transferring the print pattern of the transfer film onto the surface of the article using the water pressure to form a decoration layer.
The transfer film used for this water pressure transfer method is obtained by printing the print pattern on the water-soluble film by gravure printing method etc., but since this transfer film is kept in a dry state after the print pattern is formed, when the water pressure transfer should be performed, the ink of the print film is activated from the dry state to the state where it has an adhesion and thereafter the print pattern of the transfer film is transferred underwater in the state where the adhesion is reproduced.
The applicant has proposed a method of applying a non-solvent type ultraviolet ray hardening resin composite on the print pattern in order to activate the dried print pattern to permeate the non-solvent type ultraviolet ray hardening resin composite into the print pattern whereby an adhesion of the ink of the print pattern is reproduced by a photo-polymerization monomer of the non-solvent type ultraviolet ray hardening resin composite, transferring under water pressure the thus adhesion reproduced print pattern to a surface of an article and thereafter irradiating an ultraviolet ray onto the print pattern having the ultraviolet ray hardening resin composite permeated therein to harden the print pattern (see Patent Documents 1 through 3).
This method is advantageous because the print pattern is hardened and also a physically and chemically excellent characteristic is imparted to the print pattern by hardening the ultraviolet ray hardening resin composite permeated into the print pattern.
On the other hand, after the print pattern is transferred under water pressure onto the surface of the article, there have been tried various methods for matting a decoration layer formed by the print pattern. One of the methods is the method in which a topcoat layer is applied on the print pattern transferred under water pressure on the surface of the article to thereby matte the print pattern. However, this method is not preferable because two steps of water pressure transfer and application of the topcoat are required. Furthermore, since this method imparts the matting effect all over the surface of the print pattern, there cannot be imparted a partial matting in which the matting effect is applied only to the design (pattern) at its predetermined portions.
Another method is a method of blending a matting agent with the activating agent to thereby matte the print pattern together with the water pressure transfer of the print pattern. Although this method can carries out the matting together with the water pressure transfer, since this method presupposes the use of the conventional solvent type activator, this method cannot be applied to the case where the print pattern is activated by the ultraviolet ray hardening resin composite and it is disadvantageously difficult to adjust the state of matting control because the matting is controlled by the blend of the matting agent. Furthermore, in this method, the activator lies on the back of the design (pattern), that is between the article and the pattern, there is a problem that sufficient matting effect cannot be obtained.
Further method is disclosed in Patent Documents 4 and this method is a method for imparting a gloss, but not the matting effect. This method has two hardening steps. In the first hardening step, an unevenness is never produced on the surface by an irradiation of an activity energy ray as an irradiation amount of 40% or less, more particularly of 0.1 through 25% and the whole surface is hardened sufficiently not to leave water washing marks by removing a carrier film by water flush etc. to thereby obtain a feeling of gloss (see paragraph 0037 of Patent Document 4).
Another matting method is disclosed in Patent Document 5 and in this method, a rate of water absorption of the hardening resin formation layer is 0.5 mg/cm2 or more and activity energy ray of 1% or more of the amount of irradiation required for a complete hardening is irradiated just after a print layer is transferred onto an object to be transferred whereby the matting effect can be imparted without the blend of any matting agent (see paragraphs 0009 through 0012 of Patent Document 5).
However, since the methods disclosed in Patent Documents 4 and 5 were the method in which the matting effect was imparted all over the surface, the matting could not be controlled so as to partially matte the design at predetermined portions. Furthermore, these methods substantially differ from an idea of obtaining the matting effect by forming fine wrinkles on the design surface.
On the other hand, in the method of irradiating the ultraviolet ray onto the print pattern having the ultraviolet ray hardening resin composite permeated as disclosed in Patent Documents 1 through 3, in case where the water pressure transfer is performed mainly on a three-dimensional article, an ultraviolet ray is irradiated all over the surface of the article for hardening the print pattern by the irradiation of the ultraviolet ray. Especially, in the technical art of forming fine wrinkles (fine unevenness) on the design surface to produce a gloss difference, since formation of these fine wrinkles utilizes the hardening shrinkage by the irradiation of the ultraviolet ray, when the water pressure transfer is performed on the three-dimensional object, there occurs an uneven formation of the wrinkles by the hardening shrinkage unless the ultraviolet ray is irradiated with the irradiation amount and the irradiation time of ultraviolet ray very strictly set. As a result, there is totally arranged no gloss difference, which causes a gloss non-uniformity to occur at all the portions of the three-dimensional article and therefore the stable matting design cannot be obtained. The non-uniformity of formation of wrinkles is especially remarkable in the case where the irradiation amount and the irradiation time of the ultraviolet ray greatly differs on the forward and backward faces of the conveyance direction of the three-dimensional article, such as the case where the ultraviolet ray is irradiated while the article is conveyed by an automatic conveyor used for a mass-production line.